Strong flux pinning by columnar defects with directionally dependent morphologies in GdBCO-coated conductors irradiated with 80 MeV Xe ions

Abstract

Abstract We show that Xe ion irradiation with 80 MeV to GdBa 2 Cu 3 O y -coated conductors creates different morphologies of columnar defects (CDs) depending on the irradiation angles θ i relative to the c -axis: continuous CDs with a larger diameter are formed for oblique irradiation at θ i = 45°, whereas the same ion beam at a different angle ( θ i = 0°) induces the formation of discontinuous CDs. The direction-dependent morphologies of CDs significantly affect the angular behavior of the critical current density J c . In particular, low-energy irradiation defects induce further improvement of J c in a unique combination of irradiation angles of θ i = 0° and ±45°: discontinuous CDs at θ i = 0° and crossed CDs at θ i = ±45° provide correlated pinning in a wide angular range, which is more strongly enhanced by each other via the pinning of kinks.